This study was aimed at investigating the potential of
cell-free DNA (
cfDNA) as a
biomarker for
colorectal cancer prognosis. Sixty patients with
colorectal cancer who had not undergone surgery were enrolled as study group. Their peripheral blood samples were collected, and peripheral blood of 30 healthy volunteers (control) was collected. The
cfDNA concentration and integrity were determined using q-PCR so as to ascertain if
cfDNA was associated with clinical presentations of the disease. Then, the specificities and sensitivities of
cfDNA, CFA and CA199 were determined with ROC curve. The level and integrity of
cfDNA in patients with
colorectal cancer before surgery were significantly higher than those in patients with
colorectal cancer after surgery, and
cfDNA concentration of
colorectal cancer patients after surgery was also significantly higher than that in healthy control group. However, the integrity was not significantly different from that of control group. There was a significant correlation between
cfDNA concentration and TNM stage, differentiation degree and CEA expression, while
cfDNA integrity was significantly correlated with TNM stage and degree of differentiation. Moreover, specificity and sensitivity of
cfDNA concentration and integrity were higher than those of CEA and CA199. The TNM stage and
cfDNA concentration were independent risk factors for progression-free survival (PFS) in
colorectal cancer patients. In conclusion,
cfDNA concentration and integrity were more sensitive and specific than traditional
tumor markers (CA199, CEA). Thus, changes in
cfDNA changes can be effectively used to determine the prognosis of postoperative
colorectal cancer patients.